Once upon a time, in 1990, a young woman called Joanne Rowling found herself stuck on a train and decided to start writing.

More than a decade later, her creation, Harry Potter, has become one of the UK's biggest cultural exports ever.

Now known as JK Rowling, her books have sold tens of millions of copies worldwide, and in 2001 her annual earnings were estimated at over £24m.

Three UK publishers - Penguin, Transworld and HarperCollins - are said to have turned down Rowling before Bloomsbury snapped her up, paying a reported £10,000 for the rights to Harry Potter and The Philosopher's Stone.

The Philosopher's Stone was published on 30 June, 1997, and immediately snapped up by US publisher Scholastic for around £100,000.

An "adult" cover for the first Potter novel

By November 1997, it had been published in eight countries, had sold 30,000 copies on the UK, and won the first of many prizes - a prestigious Smarties Book Award.

In July 1998, the second Potter book - The Chamber of Secrets - shot to number one in the bestseller list, elbowing aside the likes of John Grisham and Terry Pratchett.

Rowling spots adults are reading the books too.

JK Rowling was surprised to find adults reading her novels

"A friend saw a man on a train reading a copy behind his newspaper. And at
signings adults are happy to admit that that it's for themselves," she observed.

July 1999 saw the launch of book three in a blaze of publicity.

The UK release of Harry Potter and the Prisoner of Azkaban was delayed until mid-afternoon, ostensibly to prevent children in England and Wales from skipping school to get their copy.

It had a print run of 200,000 - 30,000 more than 1999's other publishing blockbuster, Hannibal, Thomas Harris' follow-up to The Silence Of The Lambs.

In 2000, the initial UK print run for Harry Potter and The Goblet of Fire has was put at up to 1.5 million, while 3.8 million copies hit US shelves.

Again, this was nothing compared to the hype surrounding the first Harry Potter film, released in November 2001.

The contract with Warner Brothers was signed in October 1998 after months of talks and a year of speculation.

By January 2002, it had taken over £60m in the UK and £220m ($311m) in the US.

Director Chris Columbus is charged with bringing Potter to the big screen in Harry Potter and the Philosopher's Stone. It is known as The Sorcerer's Stone in North America.

The film's three stars were unveiled in 2000

When he landed the job, he said he was "thrilled and honoured", adding: "From the first time I read Harry Potter with my children, I fell in love with these wonderful characters and this world."

He put together an impressive cast to support Daniel Radcliffe as Harry, Rupert Grint as Ron Weasley and Emma Watson as Hermione.

Robbie Coltrane played Hagrid, while Dame Maggie Smith took the part of Minerva McGonagall. Alan Rickman appeared as Professor Snape.

Kenneth Branagh joined the cast for Harry Potter and the Chamber of Secrets.

But its opening was overshadowed by the death of Richard Harris. The legendary Irish actor had found a new generation of fans as headmaster Albus Dumbledore.

Not everyone is a Harry Potter fan. In October 1999 a group of parents in the US accused the books of depicting "sheer evil".

Ouija boards were burned along with Potter books in 2001

"The books have a serious tone of death, hate and lack of respect," Elizabeth Mounce from Columbia told school authorities.

Meanwhile, a teacher at a primary school in Georgia was asked to stop reading the stories to pupils after worries about its references to the supernatural.

In the UK, the head of a Church of England school in Kent banned pupils from reading the books for going against the Bible's teachings.

Carol Rookwood of St Mary's Island School, Chatham said they did not fit in with the school's "church ethos".

A website - Muggles For Harry Potter - was set up to defend his good name.

Back in the US, a Pennsylvania author took legal action, claiming the Potter series plagarised a 1984 work - The Legend of Rah and the Muggles - which includes a character called Larry Potter.

A pile of Potter books were burned in New Mexico in December 2001 by a religious group who claimed Harry was "the devil", while some fans turned against Warner Brothers after legal skirmishes over unofficial Potter sites.

A preacher in Lewiston, Maine, marked The Chamber of Secrets' release by holding a party in which he shredded copies of Potter books.

Harry Potter is being credited with encouraging children to read - as mentioned when JK Rowling received an honorary degree at St Andrews University in 2000.

The Scottish institution's Sue Cunningham said she had proved that children's books "are still capable of capturing and enchanting an immense audience, irrespective of the compteing attractions of television, Nintendo, Gameboy and Pokémon".

"At a time when dire predictions were being made for the future of books, children are redisovering the pure joy of reading."

Potter's magic is also reaching the corridors of power - Northern Ireland First Minister David Trimble is said to be a fan.